In general network traffic on a data communications network has been described as bursty or fractal in nature. The volume of traffic if examined over time shows the self-similar characteristic of peaks and valleys at consistently diminishing time intervals (see, e.g., FIG. 1 where BW.sub.MAX is the maximum bandwidth). In other words, the network sustains periods of high traffic and low traffic. Additionally, even smaller intervals of time than those illustrated in FIG. 1 can also be generally described as fractal or bursty as well. Modeling or designing hardware to handle the bandwidth requirements of this sort of bursty traffic has been fraught with difficulties. In general attempts to control the rate of frame transmission have had a depressing effect upon the overall channel bandwidth. An entire taxonomy of schemes exist to handle flow-control, from transmit windowing, and relatively recently, in-band communication of transmit delay timers, to creation of minimum frame sizes.
For example, a minimum frame spacing ("MFS") scheme has a purpose or intent of delaying transmission by stuffing a fixed number of flag bytes between successive data frames or slots. A problem with implementing MFS with this type of traffic is that although it successfully dampens the transmit rate, this scheme does so indiscriminately. All frames are padded with flags whether or not they need to be padded (see, e.g., FIG. 2 wherein BW.sub.MFS is the bandwidth using the minimum frame spacing scheme and dBW.sub.MFS is the bandwidth difference or change between the maximum bandwidth). The net effect is to reduce the overall effectiveness of the device and waste bandwidth.
Another example can be seen in the Institute for Electrical and Electronic Engineers ("IEEE") specification no. 802.3 which requires frames smaller than 64 bytes to be padded with sufficient bytes such that this minimum frame size is satisfied:
The number of extra bits shall be sufficient to ensure that the frame, from the destination address field through the FCS field inclusive, is at least minFrameSize bits. The content of the pad is unspecified. (IEEE 802.3, p. 21). PA1 In half-duplex mode at operating speeds above 100 Mb/s . . . appending non-data symbols, referred to as extension bits, to frames which are less than minFrameSize+extendSize bits in length so that the resulting transmission is at least one slotTime in duration.
Additionally, the IEEE 802.3z committee recently introduced a concept called "Carrier Extension" as set forth below:
The IEEE implementations, however, are fixed on 64 bytes as a minimum frame size. The IEEE 802.3 specification requires that padding be inserted into the interior of the frame, that is, between the data and FCS fields. The IEEE 802.3z committee development is an attempt to avoid increasing the minimum Ethernet frame size by increasing the minimum slot-time for gigabit Ethernet to 4 k bit times which is again a hard constant.